Research into the cause of color in black diamonds is relatively recent. Today we know that most naturally colored black diamonds get their color from large quantities or clouds of minute mineral inclusionssuch as graphite, pyrite or hematite that extend throughout the stone. These diamonds may also have numerous cleavages or fractures that are stained black or have become black because of graphitization. It is the concentrations of these internal features that are responsible for the coloration. In fact, the actual body color of a natural black diamond may range from near-colorless to brown or “olive” green.

Natural-color black diamonds typically are completely opaque, with a high luster that gives the stones an almost metallic appearance. And because these diamonds are so heavily included, cutting and polishing them can be difficult. They also must be set with great care.

However, a fine natural-color black diamond is a beautiful stone, with a distinctive look unlike other diamonds in the marketplace. They are often more affordable than other diamonds, too.